报告题目：

New lattice-Boltzmann schemes of the Navier-Stokes equations on non-standard grids

报告人:                     Prof. Lian-Ping Wang

                                Department of Mechanical Engineering, University of Delaware, USA

时间：2015年7月18日(周六)  9: 30     

地点：中国科学院力学研究所主楼344会议室

报告摘要：

The standard lattice-Boltzmann scheme for fluid flow simulation is based on a square (in 2D) or cubic (in 3D) lattice grids. In this talk, we discuss a few new LBM schemes on non-standard grids that are capable of performing correct simulations of the Navier-Stokes fluid flows for the first time. Specifically, three new lattice Boltzmann schemes have been developed for the Navier-Stokes equations on a rectangular grid in 2D using the MRT (multiple-relaxation-time) collision model. In the first scheme, an additional degree of freedom was introduced into the MRT (multiple-relaxation-time) collision model, to restore isotropy of the transport coefficients. In the second scheme, we inverse-designed the equilibrium moments for correct Navier-Stokes equations. Furthermore, we show that the latter can be accomplished on a rectangular grid, even with the BGK collision model. In 3D, we have designed an LBM-MRT model using a cuboid lattice, namely, a grid with different grid lengths in different spatial directions. By using the Chapman-Enskog expansion and the same transformation matrix as in the cubic LBM-MRT model, we construct a proper model for the Navier-Stokes equations by modifying the equilibrium moments to include proper elements of the viscous stress, in order to restore viscosity isotropy. The form and the coefficients in the modified equilibrium moments are determined through an inverse design process. Another function of the modified equilibrium moments is to offer the possibility of adjusting the fluid viscosity after the relaxation parameters are prescribed. The resulting 2D and 3D LBM schemes on rectangular and cuboid grids have been validated through several benchmark cases.

报告人简介：

Lian-Ping Wang is a professor of Mechanical Engineering and Professor of Physical Ocean Science and Engineering at the University of Delaware.  Dr. Wang received his B.S. in Mechanics from Zhejiang University, China in 1984, Ph.D. in Mechanical Engineering from Washington State University in 1990 and did post-doctoral work in turbulent dispersed flows and turbulence physics at Brown University and Pennsylvania State University before joining University of Delaware in 1994. He held visiting appointments at National Center for Atmospheric Research in the US, Chinese Academy of Sciences, Peking University, and is currently a Chang Jiang Visiting Professor of Huazhong University of Science and Technology and Affiliate Scientist of the U.S. National Center for Atmospheric Research.

Dr. Wang uses advanced simulation tools and theoretical methods to study multiphase flows and transport in engineering applications and environmental processes. His research covers direct and large-eddy simulations of turbulence and particle-laden flows, modeling and parameterizations of dispersion and turbulent collision of inertial particles, and simulation of interfacial multiphase flows. He explores the use of lattice Boltzmann, pseudo-spectral, and finite-difference / finite-volume methods for a variety of applications, as well as their scalable implementations on Petascale computers.  Dr. Wang is a Fellow of American Physical Society.

报告联系人：沈楠  (office@lnm.imech.ac.cn 82543935)